Breast density is a significant breast cancer risk factor assessed from mammograms. Due to measurement difficulties and the lack of automation, breast density is used mainly for research purposes and not for breast cancer risk purposes in the clinical environment.
Full field digital mammography (FFDM) is replacing film-mammography. This may be a benefit for automated measurement developments because film-images are sometimes difficult to process in part to markings and anomalous regions located in non-breast area portion of the image. In contrast, FFDM images lack off-breast area anomalies. Although there are various FFDM manufactures, there are two predominant FFDM technologies used today consisting of direct and indirect x-ray capture systems, producing images with different characteristics. The data representation produced by FFDM systems may vary due to the x-ray detection technology, x-ray generation, or post acquisition processing. FFDM systems produce both raw and processed representation mammograms.
Typically, the processed images are used for clinical display purposes, whereas the raw images are normally not considered in the clinical evaluation. A given clinical display, or processed image, is derived from its respective raw image with methods developed by the unit's manufacturer and may be mated to its clinical display apparatus. It is not clear if both representations support breast density measurements similarly, if there is a preferred representation, or what role the technology plays relative to automated measurements. It is often the case that operator-assisted methods can overcome data representation differences that appear as obstacles for automated measurements. Therefore, when developing an automated breast density measurement, it is important to understand factors that may influence its performance, which could either attenuate or enhance its associations with breast cancer.